Figure 7
Gremlin expression is modulated by Tgfβ signaling in the early limb bud. (A) Charts shows QPCR results for different genes from limb explants of stage HH20/21 cultured for 18 hours in control media (grey bars) or supplemented with 0.033 μg/ml Tgfβ1 (white bars). From left to right we show results for gremlin, fgf8, fgf10, scleraxis, sox9 and myoD. Each pair of bars shows control sample on the left and experimental situation on the right. The level of expression in controls was used as calibrator for each gene. Only Gremlin expression shows significantly lower levels of expression after Tgfβ treatments. (*) p-value ≤ 0,05 using control expression level as calibrator. (B) In situ hybridization showing down-regulation of Gremlin 8 hr after the implantation of a Tgfβ1-loaded bead (*) in the right wing bud. (C-D) expression of Fgf8 in control (C) and Tgfβ treated limb explant (D) after 20 hr of culture. Note that expression is similar in control and experimental explants. (E-F) expression of Fgf8 in the AER of control (E) and experimental limb bud (F) 30 hr after the implantation of a Tgfβ-bead in the mesoderm subjacent to the AER (arrow). Note the irregularity of the expression domain in the experimental limb in comparison with the control untreated limb.